The present invention relates generally to the field of systems for monitoring and protection of mechanical systems. More particularly, the invention relates to a technique for providing sophisticated and interdependent voting logic in monitoring and protection systems so as to permit adaptation of a control or protection scheme to specific applications.
In the field of industrial equipment monitoring and protection, a wide range of components and systems are known and presently in use. Depending upon the nature of the underlying mechanical system, the monitoring and protection components may generate various signals representative of dynamic conditions. The signal-generating components are typically sensors and transducers positioned on or otherwise closely associated with points of interest of the machine systems. The signals are applied to monitoring circuits, typically somewhat remote from the points of interest, and are used to analyze the performance of the machine system. Machine systems thus instrumented may include rotary machines, assembly lines, production equipment, material handling equipment, power generation equipment, as well as many other types of machines of varying complexity.
A variety of unwanted conditions may develop in machine systems that can occur rapidly, or develop over time or in certain situations, such as loading or due to wear or system degradation. Where unwanted conditions appear, various types of response may be warranted. For example, the response of the monitoring and protection components to different dynamic conditions may differ greatly depending upon the machine system itself, its typical operating characteristics, the nature of the system, and the relative importance of the conditions that may develop. Such responses may range from taking no action, to reporting, to logging, to providing alerts, and to energizing or de-energizing parts or all of the machine system.
By way of example, one type of condition that may be monitored in rotary and other dynamic machine systems is vibration. Information indicative of vibration may be collected by accelerometers on or adjacent to points of interest of a machine, and conveyed to monitoring or control equipment. The information from the accelerometers is not typically useful in its raw form, and must be processed, analyzed, and considered in conjunction with other factors, such as operating speeds, to determine the appropriate response to existing or developing conditions.
Responses to monitored signals and processed data, such as vibrational data, may differ due to a number of factors. Again, these may include the normal operating characteristics of the machine system. Also, however, particular bands or ranges of speeds or frequencies may be of particular interest due to the relatively greater impact of system response at such frequencies. Moreover, during certain operating periods, such as during startup or a change in speed or loading, the various ranges may be of greater or lesser interest in deciding upon an appropriate response.
Existing monitoring and protection systems, such as those used to monitor vibrational data do not provide a desired degree of versatility in configuration to accommodate such factors. In particular, where different monitors are positioned adjacent to different points of interest in a machine system, responses may typically be coordinated by a central monitoring or control system. The resulting reaction times may be unacceptably long, the resulting system is somewhat less adaptable than would be desirable. That is, where centralized control is implemented, flexibility and adaptability of the system to a more distributed, and generally more rapid, control by the individual monitoring modules is sacrificed.
There is a need for a more flexible and distributed approach to monitoring and protection systems. Moreover, there is a need for systems that can implement relatively sophisticated control or protection logic in a more distributed and interdependent fashion between various monitoring modules applied to a complex machine system.
The present invention provides a monitoring and protection technique designed to respond to such needs. The technique may be applied in a wide range of settings, but is particularly useful for controlling components of relatively complex machines, such as material handling equipment, rotary equipment, production equipment, and so forth. The monitored parameters may also vary widely, although the technique is particularly well suited to monitoring and controlling dynamic operating conditions of machines. Similarly, the responses implemented may vary, although these will typically include the energization or de-energization of components, such as via relay circuits.
The technique makes use of voting logic that is distributed among different monitoring modules and/or relay circuits. The monitoring modules are positioned proximate to points of interest in a machine system where dynamic operating conditions are monitored via sensors or transducers coupled to the various monitoring modules. The modules preferably communicate with one another via an open industrial data exchange protocol. Voting logic is stored within each monitoring module and the logic of at least one device is based upon logic, or output signals resulting from logic of another module. The logic may be user configured to permit various combinations of conditions to exist before desired responses are taken.